The invention relates to autostereoscopic displays, comprised of a flat display for representing the two stereo images, an image separating mask with vertical periodic structures for channeling the left and right stereo images onto the left and the right eye of a viewer, and a device for horizontally moving the image separating mask in accordance with the position of the viewer.
For stereoscopic representation without auxiliary means, dual channel methods and arrangements are already known that represent the left and right stereo images on a monitor, preferably on a flat display.
With these arrangements, the two stereo images, one for the left eye and one for the right eye (referred to in the following to as left image and right image), are represented simultaneously on a flat display that is organized like a matrix in rows and columns. For channeling the left image onto the left eye and the right image onto the right eye, different masks, referred to in the following as image separating masks, are used. The best known ones employ strip-shaped barriers or lenticules.
With strip-shaped barriers as image separating masks, the left image is simply blocked from the right eye and the right image is simply blocked from the left eye. When employing lenticules, the left image is projected onto the left eye and the right image is projected onto the right eye.
Generally, the image separating masks act based on pixel columns, for example, the pixel columns having an uneven number are visible only for the left eye and the pixel columns having an even number are visible only to the right eye. The image separating masks are in general periodic arrangements of vertical strips for barriers or cylinder lenses for lenticules that are oriented in the direction of the columns of the flat display. The periodicity distance between two neighboring pixel columns is referred to as pitch.
When the viewer is positioned at the predetermined position, he can view the stereo illustration without cross-talk. When the viewer moves laterally, the left eye increasingly views portions of the right image and the right eye views portions of the left image. Arrangements with pixel column separation of the stereo images have the disadvantage that the lateral tolerance range of the viewer is very minimal for stereoscopic viewing without cross-talk. Moreover, the viewer has only a minimal tolerance range in regard to his distance from the flat display.
Since the pixels generally are composed of three color subpixels positioned adjacent to one another, the image separating masks can also be organized based on subpixels. Arrangements are known that perform channeling of the left image onto the left eye and the right image onto the right eye by image separating masks that are organized based on subpixels. The problem in this connection is that the pixel correlation can no longer be maintained. For example, the green subpixel of the uneven-numbered columns is no longer projected onto the left eye but onto the right eye.
The problem can be solved by re-coding (Stereoscopic Display Device, 1995, JP 07013119 A) or by a new design of the flat display (Flat Stereoscopic Image Display Device and its Production, 1994, JP 6046461).
Particularly advantageous is the use of lenticules as image separating masks that significantly increase the lateral tolerance range for stereoscopic viewing without cross-talk, maximally to the distance between the eyes of the viewer.
In order to further increase the tolerance range that is free of cross-talk, the image separating masks can be designed to horizontally track the position of the viewer.
Methods are known in which an image separating mask that is organized based on pixels horizontally tracks the position of the viewer. Depending on the lateral tolerance range of the viewer, the horizontal movement is several pixels wide. In general, this corresponds to several millimeters.
Disadvantageous are the high requirements posed on the mechanical parts in order to realize the tracking action of the image separating masks that are organized based on pixels or subpixels.